Telephones no longer just transmit and receive telephone calls. Devices including cellular telephones, PDAs, laptop computers, and so on, collectively referred to as user equipment (UE), may transmit and receive telephone calls, may transmit and receive text messages, may participate in video-conferencing, may participate in multi-player gaming, may share content, and so on. These types of activities may be referred to collectively as multimedia services. In some cases these multimedia services may be provided over the Internet using the Internet Protocol (IP).
An IP multimedia core network subsystem (IMS) includes core network (CN) elements for providing IP multimedia services. These IP multimedia services may include telephony (e.g., Voice over IP (VoIP)), push to talk over cellular (PoC), text messaging, and so on. Conventionally, services may have been provided by a stand-alone electronic system, computer, and/or computer system. In the IMS environment, services are hosted by an application server (AS). An AS may be a physical and/or logical entity. A single AS may host multiple services (e.g., telephony, messaging) and/or a single service may require more than one AS. An AS may be described by data that characterizes various attributes like a service provider location, capability, availability, and so on.
An IMS may define how requests for service are routed to an AS that can provide the service. An IMS also may also define which protocols are supported in a communication network, how a user is charged, and so on. Services are not provided in a vacuum. User demand may provide a rationale for providing services. Furthermore, not all services are provided free of charge. Thus, organizations may establish an IMS to facilitate providing services to users, tracking usage, and charging users for services provided, among other things. Therefore, data concerning users and application servers may be stored. Furthermore, data concerning how an AS may interact with user data may be stored.